Communications systems such as wireless communications systems comprising wireless networks, in which a user equipment (UE) such as a mobile handset communicates via wireless links to a network of base stations or other wireless access points connected to a telecommunications network, have undergone rapid development through a number of generations of radio access technology. The initial deployment of systems using analogue modulation has been superseded by second generation (2G) digital systems such as GSM (Global System for Mobile communications), typically using GERA (GSM Enhanced Data rates for GSM Evolution Radio Access) radio access technology, and these systems have themselves been replaced by or augmented by third generation (3G) digital systems such as UMTS (Universal Mobile Telecommunications System), using the UTRA (Universal Terrestrial Radio Access) radio access technology. Third generation (3G) standards provide for a greater throughput of data than is provided by second generation systems; this trend is continued with the proposals by the Third Generation Partnership Project (3GPP) of the Long Term Evolution (LTE) system, using E-UTRA (Evolved UTRA) radio access technology, which offers potentially greater capacity and additional features compared with the previous standards.
LTE is designed as a high speed packet switched network, and voice and SMS services are provided as packet switched services such as Voice over Internet Protocol Multimedia Subsystem (VoIMS) and SMS over IMS (typically referred to as SMSoIP), whereas previous generation systems such as UMTS support voice and SMS services that are primarily circuit switched. Therefore, for LTE, both data and voice services are provided by a packet switched network, and a circuit switched connection is generally not available. The packet switched network is typically “always on”, so that following a successful initial attachment, a UE remains connected to one or more packet switched data networks.
It is sometimes desirable to inhibit or prevent transmission of some or all types of user data to and from the user equipment. For example, in 2G and 3G networks, the user is often provided with the option of disabling (by e.g. altering a setting on his or her UE) transmission of all types of user data other than voice and SMS data; in particular, voice and SMS user data are often subject to charges which are different from (typically lower than) charges for other types of user data. This may be particularly useful in situations in which the UE is “roaming” i.e. connected to a visited network, in which higher charges may apply than when the UE is connected to its home network.
However, it is not straightforward to inhibit transmission of user data in packet switched networks such as LTE, since, as described above, it is designed as an “always on” connection. In particular, it is not straightforward to distinguish between different types of data since, in LTE, all data is transmitted according to a packet-switched method.
It is an object of the invention to at least mitigate some of the problems with the prior art systems.